Helo PrepHole
I make artificial reefs out of concrete and take them out to the water so fish and animals can live around and on them.
I have a new design and am wondering the easiest way to make a concrete mold.
Silicon, fiberglass, or ABS, or something else. I have space and tools available, I am also willing to spend some money to have parts made, i am just wondering the best, and cheapest method. Mold is kinda large, like 14 inches + per side, so not sure if a 3D printer could be used.
Here is the general plan, a unit shaped like this, the depth of the unit would be almost the same as the notches you see in the side so the units would be linked into a 3D structure making houses for sea life.
Also, I'd round those corners for stress concentration.
You could just cut/drill this shape from pre cast slabs or tiles.
But for moulding I would recommend silicon, it won’t be cheap but it’s easy to remove the product and lightweight when empty.
Metal with a removable backing would be easy as well, and cheaper: you could just bend a strip of aluminium or steel to match the perimeter and add some tube on the backing for the central hole
as a spearfishing gay, i'll tell you that fish LOVE ledges.
I would try to make shit like what you posted in the OP or anything that will create a ledges where they can hide.
is that a top down view or does it stand up?
Here is how they would (hopefully) stack underwater, provided I get the tolerances right.
The unit would have surface area for invertebrates and empty space inside for fish and other creates that needs protection from predators.
Ask a local precast mob,
The team here from Wagner's is standing in front of a piece for the bogo road train station. These were cast on their side with the holes in the middle made with a box with retractable struts in the middle (a guy would have to climb in to retract the struts after knocking out extra pieces of moulding) and flip up walls on the outside. The base of the mould was a concrete slab. You should be able to use a tube in the middle flip up walls for the outside and walls held up by each other with struts for the notches. You also may want some beams to run across the top of you mould to hold it open to the right dimensions as well
Tldr ask a local precast mob.
I'm on my computer now an I read the op so I now know what size we'll dealing with.
I recon if you are to continue making the pieces use a steel mold similar to what is used for tunnel sections but flat.
It would be easy but I think you would only get one use from the mold.
Depends how smooth the cut is. If you use a foam knife it should be pretty non-porus, and you can line it with wax paper or spray mold release if you want. I used it to make pavers and got about 10 uses out of each sheet before they blew apart but I didn't reinforce it at all. you could probably screw it to plywood or something to make it less prone to snapping.
okay I don't know much about the stuff, I just heard foam and thought of the stuff cheap eskies are made of.
oh shit should have read b4 posting kek
that is very cool
Why not just make it out of steel? How many of these are you looking to make? I don't know alot about concrete molds, but I imagine that ABS might break or become brittle from UV(I would think you are making it outside.)
I've tried welding a mold before, with a shape like this I could imagine it might be really hard getting the cured concrete structure out, even with a release agent. Heavy, expensive, and it would be hard to make it as exact as I need need.
ABS if I remember correctly is pretty UV resistant, and only shows photodegredation after years of exposure.
If you are going to cast them, I would say that a silicone mold with a mother mold around it would be your best bet. Casting those shapes might not be the best way to make those with longevity in mind, though.
Either way, I want updates. Cool project, anon.
I do have some experience with silicon. I take it the "mother mold" is a stiffer outer mold to keep it from flexing?
Also how would I make the positive to pour the silicon around? 3d printing?
Why not some wood? Your geometry isn't that complex.
Already tried that, I made a wood mold that I can take apart with flanged wingnuts, I lubed it up well with mold release, and I still could not remove it from the mold once cured.
Melamine works best, it’s non-porous and suitable for repeated usage providing you’re gentle. Theres also a special plywood made for formwork, can’t remember what it’s called but the face veneer is plastic.
I've tried melamine before with molds. Once any water gets into the wood portion it swells, I'd imagine it would last me just a couple of units. I'm looking for something more robust and long last.
I will look into the plywood you mentioned.
Go buy some large cutting boards made of HDPE. Cut them down. Join them with screws on the outside of the mold if you need to.
You're thinking about Medium or High Density Overlay panels (MDO/HDO) Plyform is one brand. Also used in the sign industry for exterior sign blanks, has both a waterproof overlay and uses exterior grade glue for the lamination.
I would use something like this that screws together and gang up multiple pieces in one mold, like three at a time.
All it really needs to be is a rectangular tray with rigid plastic or metal dams between the tiles and separate blocks placed where you want the indentations and a round plug for the center hole...that will make removing the mold easier and the blocks/plug could be made of rubber or even sacrificial Styrofoam or homasote to make it even easier.
use HDO plywood (high density overlay)
It's specifically made for exactly this application. You still need to oil it, though
Maybe sand the plywood or hardwood smooth then impregnate the wood mold with silicone lubricant spray.
I thought this too. A white supremacist who defies Islamic Rule might use a square wooden Box. Wood Sprayed with silicone lubricant oil. with the 4 upright sides mounted on at least four hinges to peel down away the 4 sides. 4 precise square inserts mounted on the hinged upright sides. A random shaped center hole insert. Benefactors donating to the project can choose the hole shape and size: israelites. Christians, blacks, Muslims. To convert the fishes to their cause.
Ask local cement contractors or bribe cement truck drivers to donate their surplus cement. They just dump it anyway. Drive to them and catch a few 5 gallon buckets of concrete or bring your molds to the dump site.
Once I get some out in the water, I will be sure to follow up with some photos, I have a pretty neat underwater camera.
Maybe I'll even take a before and after, as once a structure has spent half a year underwater, they're covered in life.
If you run a small current through the rebar the concrete will self-grow and self-heal
https://en.wikipedia.org/wiki/Biorock
>https://en.wikipedia.org/wiki/Biorock
I dive in cold water, calcium carbonate has retrograde solubility, its much easier to make Biorock in warm water.
That's really interesting. I didn't know that. Man, chemistry is weird sometimes.
Why not make a positive mold and use it to create negative molds in sand?
Still going to have the same issues with getting the positive mold (plug) out of the sand without damaging the impressions.
The shape is simply not conducive to easy removal, the same alternating 90° angles that allow the units to "key" into each other in a locked fashion key them into a female mold or key the plug into material molded around it to create a female mold.
> The shape is simply not conducive to easy removal
That’s false, it’s a 2d shape, it’s fully removable in the direction of the hole, so if you can’t remove this with your process, you can’t remove any shape easily. HDO plywood is made for this but if you really struggle, make a wood mold and then add an inch of silicone on the inside so you’ll have a flexible layer
>it’s a 2d shape
LMMFAO
Hey, now there is a great idea, I will have to see how well my local sand holds up to deforming, like greensand. As I states the depth of the resulting unit has to match up quite well with the side notches or else the unit either doesn't slide together, or its rocks around too much.
Thanks for a great idea though.
Is that legal where you live?
Yes it is. We do not, and can not harvest any marine life, nor do I want to.
I volunteer at a moderately sized marine protected area (MPA), we have permission to enhance areas for marine life and divers alike.
>I volunteer at a moderately sized marine protected area (MPA)
Wait... jannies have evolved gills?
we call them "sea jannies" out here
What do they eat?
air pockets
concrete seems like a waste, i would just make them out of old car batteries.
You laugh, but its amazing how many people in the past thought that just throwing batteries in the ocean was acceptable. There are divers in my area that clean up batteries around old boat launches and harbors.
doesn't look like there are any fish around, you sure those contraptions aren't scaring them off
I took those photos when those structures had been underwater for about an hour
Buying concrete for this work is foolish and carbon offensive. Salvage wet concrete from sites where cement truck dumps surplus concrete. Bribe the cement truck driver to txt you the dump location.
You could also just ask city to donate broken pulled up concrete sidewalk slabs or concrete blocks and then stack these with gaps and holes for the fish in the ocean. The fish don't care about uniformity or asthetics. Also heavier slabs and chunks will resist rogue waves.
this is the only way it makes sense.. even then you have to ask yourself what's in the concrete and if it's a net benefit. Lots of concrete contains fly ash which is full of heavy metals.. so maybe contact some sort of environmental monitoring group to run some numbers.
if you're OK with fairly complex molds, try making some fractals. a Hilbert curve with a roof could make a lot of hidey holes for the fishies
As cool as it would be to build intricate 3D structures all ready to be floated out into the water or taken out on a boat. I’ve found out a while ago it’s better to have simple structures that can be linked together underwater. While concrete can be strong it’s not unbreakable. And the process of moving it down the beach can be stressful on something like you mentioned. Also, there is materials savings when you can make something flat like I plan on making.
Stop dumping waste concrete in the ocean.
Here you go buddy, this is kelp growing on “concrete waste” as you put it.
Concrete production creates more carbon dioxide that any other process. This acidifies the ocean and kills mollusks and crustaceans. Stop it. You’re doing more harm than good.
I'll refer you to the image posted above. A annual kelp that locks away much more CO2 than is released by the concrete that it grows on.
Kelp has been growing fine for millennia without concrete waste disposal.
Wrong again. Kelp is where I’m at has been suffering greatly. And up and down the west coast and in Tasmania.
> Tasmania.
Gday c**t
I have no clue if chucking concrete in the ocean is bad, but there are stacks of concrete structures in the ocean. See every single boat ramp ever lmao
Anyway in any case good work mate. I suggest just fabbing up a plywood mold for the new design and using 4 plywood walls a pvc pipe in the centre for the hole
Watch this video https://youtu.be/8F4ZJ762QfM?si=3i6RCA4TlWPgK4ok
They make a stack of different ornate concrete molds. Your design should be simple
Thanks for the image. The wood mold I made is exactly like the image you took time to create. I can upload some photos of it tomorrow. I painted several layers of hard paint on it and used a lot of mold release in it, but when the concrete cured I could still not get then sides out of the concrete. The piece that makes the notch is a real b***h to yank out of the concrete.
I’ll look at the link you provided.
I've seen people use oil or talcum powder on their molds to keep the pour from sticking
Make this, with a 2cm clearance, put a positive model in, and fill the space with urethane rubber (as per
tho in my limited experience shore 60 silicone can last 50+ times). You’ll have a fully reusable mold that will always release and you’ll get sub millimeter precision.
this might be the route I need to go down. Only downside is the gallon Smooth On mixes are like 150 dollars, and Id like to make multiple molds.
This but instead of screws use four or eight hinges on bottom of the four vertical sides and simple hasps or latches at the corners.
Yea this is a decent criticism. I do like this idea in principle.. but i have reservations about it in practice. Concrete production does require the burning of limestone which emits carbon dioxide which increases carbonic acid in the ocean which decreases aragonite saturation which causes carbonate to dissolve... but your structure is made of carbonate... So in the end if you want cause a net growth in coral reef structures, you have to increase base cation concentration in the ocean to increase aragonite saturation to increase carbonate precipitation which causes the structures like you're making to form spontaneously both biologically and chemically.. So yea noble but perhaps there are other better solutions which take a more comprehensive consideration of all the variables which impact growth and viability in the ecosystems OP seems dedicated to protecting.
the concrete is already produced :O
>the concrete is already produced
By providing a cheap disposal option for waste concrete you are encouraging over-production.
There is money available to do reuse of concrete sidewalk slabs:
"HADLEY — Facing a state order and threat of fines, a Hadley contractor has cleaned up a massive pile of concrete demolition debris that was dumped along the banks of the Connecticut River.
After investigating the site off Route 47 near Stockwell Road in March, the state Department of Environmental Protection determined that 2,860 cubic feet of concrete rubble, ... had been dumped there. The volume of material would almost fill a 48-foot semi trailer."
Wagners makes a low carbon concrete if you are worried about the concrete emitting co2 while in the water.
https://www.wagner.com.au/main/our-projects/earth-friendly-concrete-used-for-residential-project/
Concrete absorbs co2 over time not emits co2
no concrete production is a net emitter of co2 because you start with limestone, you burn fuel to turn CaCO3 into CaO, which then turns BACK into CaC03 by absorbing c02.. BUT the energy cost of the initial conversion into CaO is lost. You need to increase available calcium or magnesium or other alkalinizing minerals to increase net carbonate formation in the oceans. These minerals come from igneous rocks, primarily those which also dissolve with other nutrients like basalt.
I agree. But He can salvage surplus wet concrete that is dumped by cement trucks. He can bribe the cement truck drivers for txt of dump locations.He could also salvage clean concrete blocks or chunks from demolition sites or landfill sites.
Dump batteries instead. Checked.
put fake runes on them so the next civilization after we wipe ourselves has a fun mystery
I was thinking of marking them somehow, maybe as a way to date them, or put a benefactors name on them as a thank you.
build molds with paint buckets and foams to block out negative space
>wondering the easiest way to make a concrete mold.
XPS foam cutouts.
forgot pic. You can get the foam pieces pretty thick so you can just use a foam knife to cut out the shape, and then they should slide right out.
OP I’m a concrete mold maker by trade. I taught myself and no offense, I’m not going to tell you because I’m a phone poster and it’s very time consuming making posts. I’m very busy, apologies. What you’re wanting to do is actually pretty simple so I think you’ll be able to figure it out.
The advice you’ve gotten in thread is not bad but seems needlessly complicated and wasteful, to me at least. Your best bet is rubber. Don’t use silicone for fricks sake. It’s extremely expensive and isn’t durable enough for repeated use with concrete. You want a urethane rubber. Preferably one formulated for use with concrete.
I use the company in the first link below for ordering. They’re fantastic. Smooth On is the company that makes the rubbers. You can also order directly from them. You can find tons of info on both their and Reynolds websites/YouTube channels to show you how to do what you need.
https://www.reynoldsam.com/application/concrete-casting/
https://www.smooth-on.com/applications/concrete-casting/
https://blog.pondking.com/designing-the-perfect-bass-habitat
https://www.in.gov/dnr/fish-and-wildlife/fishing/reservoir-habitat-enhancement-program/
Make your own version of a Symons form system with interlocking pieces attached with clips/bolts for assembly/disassembly.
Seems like a bizarre waste of labor and material
Isnt there tons of junk lying around thats already fabricated and used up that you can toss in ocean?
We look for it, but people usually just throw it away. We do get cinder blocks to make into structures and those work well. And we use a lot of natural granite boulders to make into artificial reefs as well.
Make a WANTED on Freecycle. Or Craigslist free. Contact local contractors that you will accept delivery of x, y, z at locations__.
"HADLEY — Facing a state order and threat of fines, a Hadley contractor has cleaned up a massive pile of concrete demolition debris that was dumped along the banks of the Connecticut River.
After investigating the site off Route 47 near Stockwell Road in March, the state Department of Environmental Protection determined that 2,860 cubic feet of concrete rubble, reinforcement bar, pipes, conduit and painted wood shards had been dumped there. The volume of material would almost fill a 48-foot semi trailer."
I know you said you tried steel, but I would make a new form out of steel. Make it really smooth and polished and chamfer the corners nicely. And make it so it unpins at the corners. Put it on a sheet of metal or something slick and flat for the bottom surface, or hell if you want it rough you could put it right on the ground. If you did a slick surface like melamine or a sheet of steel you could have a way of indexing something simple for the center hole. A 2l soda bottle or a plastic coffee can that is firm yet squishy enough to squeeze in and remove from the hole once the concrete has set up.
This way you unpin the sides and simply knock them away from the concrete to remove it.
Sides could be made from simple flat stock steel in whatever width you want the final block thickness to be.
Each corner "hinge" should be made so one part has one center hinge barrel and the other corresponding side has two. Do this the same all the way around so they can be pinned together in any configuration and still be correct.
Pic related is a form I made for concrete planters. The sides unpin and fold down to get it out. The inside has enough taper to get out fairly easily. I used some bolts as "pushers" to help pop it out.
Another hopefully less blurry pic.
Folded up and pinned.
maybe try the concrete mix they make cinder blocks/pavers out of. where it can be compressed, quickly dry, and removed out of the mold. you should just make the mold out of wood and a pvc pipe in the center.
thanks, thats a great idea too. I've looked looked into it some, and it seems that with my wood molds, I was using an inferior mold release agent. And I can buy products that will probably allow the mold to release from the cured unit much more easily.
If that doesn't work I'll look into another method to cast the units.
We make artificial reefs so that we have a secret, productive fishing spot to take clients to in the gulf near Destin Florida. We use old shopping carts. It works great. We now have an area of about half a football field covered in them.
>Americans will use any thing but actual measurements.
>Americans will use any thing but actual measurements.
You're an idiot with poor reading comprehension. We're dropping shopping carts into water that is over one hundred feet deep. Having an exact measurement of the area is not possible.
You can still use an approximate of an actual measurement.
>You can still use an approximate of an actual measurement.
I did use an approximate measurement, fool. Now, I recommend that you close your wiener-sucker to avoid looking more stupid than you already do.
>half a football field
>actual measurement
Yeah whatever discovery channel.
Would old and used cinder blocks work? Just use them sideways.
yes, we use those ALL the time.
You're overthinking it
Did you realise that wood floats in the water, quite unlike a concrete reef?
Did you realize there are many ways to anchor it?
Sure, it is just overly complex.
They used to transport timber in rivers around here, and the timber escaped from time to time and ended up in sea lanes, causing a lot of damages. So if your wooden reef decomposes over time, you can get into trouble.
No real problem in an inland lake full of dead trees thoughever.